1. Field of the Invention
The present invention relates generally to a multilayer planar array antenna and, more particularly, to a multilayer planar array antenna, which enables the reduction of the size thereof, extends the bandwidth thereof, and transmits and receives signals at high gain and high efficiency.
2. Description of the Related Art
As a technology relating to a small-sized plane antenna, including a conventional array patch antenna device, Korean Unexamined Pat. No. 2002-0015428 includes an array patch antenna element and a low-noise block down converter. The array patch antenna element includes a radiating substrate on which a plurality of slot pairs, each of which includes a first slot and a second slot that are arranged to form an angle of 180 degrees with a reflecting substrate, is formed, and on which a feeding line for supplying current to the slot pairs is formed, a lens substrate in which a plurality of lens holes is arranged, a first spacer which is disposed between the radiating substrate and a ground substrate, and a second spacer which is disposed between the radiating substrate and the lens substrate. The low-noise block down converter includes a lower casing in which a waveguide and a plurality of cavities are formed, and an upper casing which is coupled with the lower casing.
However, in the conventional technology, when a dual polarization antenna is implemented using a single polarization antenna, the dual polarization antenna is formed in a multilayer structure to differentiate signals for a feeding portion. Accordingly, problems occur in that the circuitry of the multilayer antenna is complicated, the efficiency thereof is lowered, and the size, weight and cost thereof increase.
Furthermore, the feeding of a plurality of radiating elements is performed at a single radiating element feeding portion, so that problems occur in that feeding loss from the feeding line occurs and the gain of the antenna is lowered.